Society's renewed interest in works of arts has resulted in the demand for inexpensive reproductions of the original. For many years, society had to contend with two dimensional reproductions which were most often reproduced by a photographic process. These two dimensional reproductions failed to reproduce what was often an essential characteristic of the work, the relief. For some paintings, for example, part of the genius of the work not only lies in the image produced but in the texture of the work such as the brush stroke, which, for example, may reflect light in a particular manner.
One of the first obstacles to achieving this goal is the manner in which the third dimension of the art work can be reproduced. Various methods have been set forth in order to recreate that third dimension, however, some of those methods involve making a matrix from the original work itself pouring a substance over the original work to copy its relief; (U.S. Pat. Nos. 4,285,744; 4,971,743; French Patents 1,493,516 and 1,548,337). Unfortunately, this procedure is simply not acceptable when reproducing originals as it may jeopardize the physical integrity of the work and with masterpieces they are simply not available for use.
From the matrix a female and possibly a male molding die is made. These dies constitute the molds against which the image carrying substrate will be pressed. The molding may be accomplished by a press, a vacuum or other devices which exert pressure on the substrate.
The problem encountered in pressing the substrate consists of finding a medium capable of adequately reflecting the definition sought. It has been found that PVC is a medium which can be properly deformed under controlled conditions. Unfortunately, this material must be heated prior to pressing and this often leads to displacements and distortions of the image contained on it.
Traditional processes have attempted to deal with the above problems in the following manner. Canadian patent application 2,020,206 and its U.S. counterparts 5,182,063 and 5,201,548 put forth an alternative method for forming a matrix which reflects the three dimensional features of the work of art, without jeopardizing the original work. A similar approach is also described in U.S. Pat. No. 4,001,062. Two photographs of the original work are taken, and are put side by side on a carrier. The transparent substrate, upon which the three dimensional elements will be reproduced, is placed over one of the images. An artist then begins recreating the relief (for instance, the brush strokes) by referring to the image underneath the substrate. When it becomes difficult to see the image beneath the substrate because it is covered with paste, then the artist may simply refer to the other image beside it. By having an artist reproduce the three dimensional elements of the original work on a matrix, and then forming the mold from that disposable matrix, the original work of art is never touched. On the other hand, one of the drawbacks of this procedure is that once the artist begins relying on the image beside the substrate, and not the one underneath, faithful reproduction of the relief becomes less accurate.
In order to ensure adequate definition during the pressing process, many prior approaches (U.S. Pat. Nos. 4,971,743; 5,116,562 and 4,285,744) require that the image carrier, which is most often a sheet of PVC, be heated to its softened state immediately prior to embossing. The PVC is usually heated to 110.degree. C. to 130.degree. C. As it is softened, the sheet of PVC bows over the female embossing die but does not come into contact with it. The press is then elevated so that the softened PVC fills all the notches and indentations of the die, and the pressure is then applied for the necessary amount of time. Unfortunately, the heating of the sheet of PVC to its softened state inevitably results in unequal softening, so that some sections of the PVC will soften more quickly than others and consequently, they will bow before others, which results in the displacement of the image. Therefore, the molded relief does not correspond with the image. In the process of U.S. Pat. No. 5,182,063, canvas is impregnated with a resinous material to form a substrate. The PVC sheet material with image is then melted and pressed against the substrate to bond the PVC sheet to the substrate. The pressing operation involves the use of dies which press the desired relieve into the PVC and substrate sandwich. Although the image appears to be stable on substrate, additional processing is required to ensure such stability.
For this reason, some inventions, such as U.S. Pat. No. 4,285,744, provide a means for molding a PVC substrate, while upholding the quality of the image, by heating it quickly to its softened state, by monitoring the distribution of the heat, and by subsequently cooling it rapidly. In other words, attempting to reduce the amount of time during which the PVC bows over the die. However, in light of the inherent structure of PVC, it is impossible to predict the manner in which it will soften, even if the heat is regulated.
The present invention in accordance with one aspect seeks to overcome the shortcomings of the prior art in the following manner. When recreating the three dimensional qualities of the original work of art on a matrix, this invention ensures that the image on the substrate remains visible at all times so that the artist does not have to make a calculated guess as to the placement of a particular relief. This is accomplished by projecting the image onto the substrate, either through the use of a standard photography lens enlarger or its equivalent. By projecting the image, the artist is always able to see the work regardless of the amount of paste covering the substrate which equally increases the reliability of the three dimensional reproduction.
Furthermore, prior to the pressing process, this invention does not require that the PVC be heated to such an extent that the sheet droops over the die, thus increasing the likelihood of distortion or displacement of the image in relation to the relief. Instead, the plastic sheet is heated to a first temperature immediately prior to molding and the temperature is increased further once the pressure of the vacuum is applied. In other words, the optimal temperature required for forming the plastic sheet is still achieved, however, this final softened state is achieved only once the plastic sheet is contained in the mold, at which point there does not remain any possibility of distortion or displacement of the image in relation to the relief.
The present invention uses vacuum as opposed to opposing presses, in order to apply the required pressure for molding the PVC. Although a vacuum forming machine may be less effective than opposing pressing of matting dies such as described in U.S. Pat. No. 4,285,744, this invention overcomes most of the shortcomings by allowing for the drilling of a multitude of minuscule holes into the female die, which will result in the increased effectiveness of the suction of the vacuum on the image carrier substrate, and consequently, this will result in increased definition of the relief embossed. Although U.S. Pat. No. 4,308,224 describes the use of microscopically small air channels in the die, they are for a completely different purpose to allow air to escape during the melting of the foil. The foil in its molten state takes on the shape of the mold as the molten foil flows into the mold and moves air out from beneath the foil through the air channels.
Although the process in accordance with this invention may not result in a three-dimensional reproduction that is as high quality as some of the other procedures, the method provides for a significant reduction in the production time.